How to Restrict Textbox Input in Hexadecimal Range

Question

Hi,
Can you please take a look at following code and let me know how I can restrict the "txtColor.Text" in a way that if user insert a wrong hex sting(value) like "KKKKKK" the exception handler handle the issue and pops a warning message to correct the input?

Here is the code:

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

namespace SimpleColorPicker

{

    public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();

        }

  

private void txtColor_TextChanged(object sender, EventArgs e)

        {

            if (txtColor.Text == "")

            {

                lblColor.ForeColor = System.Drawing.Color.MediumPurple;

            }

            else

            {

                string cc = String.Format("#{0}", txtColor.Text);

                Color col = System.Drawing.ColorTranslator.FromHtml(cc);

                lblColor.ForeColor = col;

                lblColor.Refresh();

            }

        }

    }

}

Thanks,